The present invention relates to an alarm system. It can be appreciated that alarm systems have been in use for many years and examples of such are described below.
An alarm system is shown in U.S. Pat. No. 4,583,081 issued Schmitz and published on Apr. 15, 1986. This document shows a door operator system includes up and down limit switches actuated to the closed position when the door reaches the up and down travel limits. A processor circuit within the operator is connected to the limit switches for ascertaining the position of the door. Bias circuits apply a bias to the processor when the limit switches are open. An indicator system comprising a pair of light emitting diodes connected across respective limit switches which indicates the door position. A series impedance element common to both LED circuits prevents actuation of the control circuit by the light emitting devices.
Another alarm system is shown in U.S. Pat. No. 5,402,105 issued to Doyle et al, published Mar. 28, 1995 relates to a garage door position indicating system including a tilt switch attached to a garage door, an RF transmitter coupled to the tilt switch, an RF receiver, and an indicator controlled by the RF receiver. The tilt switch supplies an enable signal to the RF transmitter at selected first tilt positions and blocks the enable signal at selected second tilt positions. The RF transmitter generates an RF signal in response to the enable signal. The RF receiver is responsive to the RF signal and controls an indicator to indicate the position of the garage door.
U.S. Pat. No. 5,499,014 issued to Greenwaldt, published Mar. 12, 1996 relates to a security alarm system includes a wireless transmitter unit, a portable control unit, and a receiver unit. The transmitter unit includes a sensor for detecting the opening of a door or window to a protected area and an alarm signal generator for providing an alarm signal wherein the alarm signal generator is controlled by the sensor. The control unit includes an arm signal generator for providing and transmitting an arm signal and a disarm signal generator for providing and transmitting a disarm signal. The receiver unit includes an alarm for indicating unauthorized opening of the door or window to the protected area, a first circuit for receiving the alarm signal from the transmitter unit and activating the alarm when the alarm is armed, a second circuit for receiving the arm signal from the control unit and arming the alarm, and a third circuit for receiving the disarm signal from the control unit and disarming the alarm and for turning the alarm off when the alarm is activated.
U.S. Pat. No. 5,781,107 issued to Ji, Wen Shu and published Jul. 14, 1998 relates to an alarm device for an automatic garage door including a detecting circuit for producing a single negative pulse signal when a detector detects an opening motion of said garage door, an alarm controlling circuit for receiving said single negative pulse signal and producing an alarm signal, a “normal function” detecting circuit connecting to a garage door opening machine for producing a “normal opening” signal when said garage door is normally opened by said garage door opening machine, which is then changed to a “shut off alarm” signal provided to said alarm controlling circuit for preventing the production of said alarm signal, an alarm generating circuit for generating an alarm when said alarm signal is received, and a transformer circuit for providing low voltage for said alarm device. Accordingly, the alarm device for an automatic garage door can provide a warning alarm when said garage door is forced to open or damaged by bandits or burglars. However, as long as the residents operate a normal remote control or in-house switch of said garage door to open or close it, said garage door will be opened and closed as usual with no alarm.
U.S. Pat. No. 5,883,579 issued to Schreiner and Schofield published Mar. 16, 1999 relates to a system which will activate an alarm when a garage door is opened. The system consists of a transmitter unit and a receiver unit. The transmitter unit is attached in proximity to the garage door. The receiver unit is located within a vehicle stored in the garage. The transmitter unit includes a signal generator which activates and transmits radio frequencies (RF) to the second unit. For activation, once the garage door is in an opened position, the transmitter sends a signal to the receiver. The receiver activates an alarm.
In WO02100222 issued to Dalgaard Allan (DK) published Dec. 19, 2002 discloses a radio-signal-based mail delivery alarm system comprising a transmitter unit provided in connection with a mailbox or mail-slot flap and a receiver unit for being located at a distance from the transmitter unit and being able to receive a radio signal emitted by the transmitter unit. The transmitter unit comprises a movement sensor for detecting movement of the mailbox or mail-slot flap and a transmitter with power supply and antenna for emitting a radio signal in response to movement of the mailbox or mail-slot flap. As opposed to the prior art transmitter units for such mail delivery alarm systems, the present transmitter unit is built integrally with the mailbox or mail-slot flap.